chase (one's) tail

To take action that is ineffectual and does not lead to progress. Refers to how a dog can exhaust itself by chasing its own tail. Come on, Bill, go to sleep. You're just chasing your tail at this point, but you might have a breakthrough with the research if you take a break from it. I'm trying not to chase my tail on this project, but so many components of it are just not working out.